Sharp PC-1211

13
Pin No .
Signal name
In /Out
Description
1 F4
Out
Buzzer signal
When the buzzer is off : Low ----i 0 . 2 5 msl--
When the buzzer is on :
LS1___J
2
F3
Out
Chip Enable signal (Display chip 3 select signal)
3
F2
Out
Chip Enable signal (Display chip 2 select signal)
4
Fl
Out
Chip Enable signal (Display chip 1 select signal)
During display : Low ----- _ _ _ _ __
During read-in: Turns mementarily high
5
VDD
Out
For liquid crystal drive voltage preparation (VDD :; V GG)
6
VGG
In
Source voltage("-" voltage of the battery)
7
VGG
In
-
8
Xin
In
Basic clock (Pulse signal in 256KHz)
11
RESET
In
All reset switch input
3 - 2. SC43178 (CPU II)
Pin No .
Signal name
In/Out
Description
-
41
Sn Out
Key Strobe signal , RAM Address signal
42 Si Out
Key Strobe signal, RAM Address signal
43
Sl3 Out
Key Strobe signal
44
Sl2 Out
45
Sll Out
During display: High
46 SlO
Out
Depression of the key causes it momentary low
47 S9
Out
48
S8 Out
49 S7 Out
50
S6 Out
51
SS Out
52
S4 Out
53
S3 Out
54 S2
Out
55
Kil
In
Key input signal
56
Ki2 In
57
Ki3 In
During display: Low
58
Ki4
In
Depression of the key causes it momentary high
59
S16b
In
Busy signal of the CPU II (high during the execution of the
(Ki5)
CPU II) I
During display : Low
Depression of the key causes it momentary high'.
n